Patient admitted in hospital with a displaced three- or four part proximal humerus fracture of OTA / AO group 11-B2 or 11-C2 (displaced fracture of extra-articular or articular, bifocal type). The subgroups -.1, -.2 and -.3 will be included for both B2 and C2 groups, provided severe displacement: This is defined as a mal-position of at least 45º of angular deviation in valgus or 30º in varus in true frontal projection, regardless of whether the fracture is impacted or not, or less than 50% contact between humeral head and the metaphyseal part of the shaft. The greater or lesser tubercle displaced at least 10 mm.